This invention relates to a high-voltage generator for electrical loads containing capacitive components, particularly for lasers.
To excite a gas discharge in electrically pumped gas lasers with dielectric input coupling, a high-frequency alternating voltage having peak values of several kV to some 10 kV is needed. Usually, tube transmitters having an approximately sinusoidal output signal at a frequency of some 10 MHz are used for this purpose.
Generators using semiconductor switches and based on the operation of switched-mode power supplies currently used in power supply systems are less expensive to produce and also to operate because of their higher efficiency. In this arrangement the alternating voltage taken from the power line is rectified, filtered and then chopped by means of semiconductor switches, at a frequency of some 10 kHz up to a few MHz. The voltage produced, having an almost rectangular variation with time, is then transformed up to the required value with the aid of suitably designed transformers and applied to the electrodes for the gas discharge. The disadvantage of this arrangement is that the electrical load applied to the generator may contain only small capacitive components in parallel with its output since, when a rectangular voltage signal is applied to a capacitor, unavoidable power dissipation arises in the internal impedance of the voltage gas discharge arrangement.
An object of the present invention therefore is to provide a high-voltage generator in such a manner that the power dissipation can be reduced even in arrangements of simple design and having higher capacitive components.